Page 1 of 1
UCL11 SE options
Posted:
Sat May 31, 2014 11:55 amby DeathRex
I'm just guessing at the resistors. Which UCL11 with the common cathode schematic do you like? Or do you have one?
Re: UCL11 SE options
Posted:
Sat May 31, 2014 1:43 pmby Geek
I'd try "A" to get your resistors all figured out, then play with "C" if distortion is objectionable.
Cheers!
Re: UCL11 SE options
Posted:
Sat May 31, 2014 4:04 pmby DeathRex
On A I thought of doing cathode to cathode feedback, all on one cathode, while C is gfb. But then A would get me less power out. I only need 10 volt pp swing, and the triode has a gain of 62.
Re: UCL11 SE options
Posted:
Sat May 31, 2014 5:02 pmby EWBrown
The 20 and 6.8 ohm resistors with 7VDC across them, will equate to 261mA, which is about 10X too much current for these tubes. Try 200 and 68 ohms.
In "C" the 470uf cathode bypass cap will defeat any NFB. "B" would probably be the best circuit, with the plate to plate NFB. The 220K resistor
would better between 470K and 1 Meg.
HTH /ed B
Re: UCL11 SE options
Posted:
Sat May 31, 2014 6:00 pmby DeathRex
EWBrown wrote:The 20 and 6.8 ohm resistors with 7VDC across them, will equate to 261mA, which is about 10X too much current for these tubes. Try 200 and 68 ohms.
In "C" the 470uf cathode bypass cap will defeat any NFB.
HTH /ed B
The feedback would go through something like a 2.2K to the junction of the 68 and 200 giving me 50 ohms to ground. But the feedback would also goto the grid of the triode. That's where the feedback would be applied. Or how about C with B's anode to anode feedback?